Electrical signaling system



Dec. 6, 1949 c. DE vRlENDT ET Al. 490,038

ELECTRICAL SIGNALING SYSTEM Filed Jan. 22, 1943 A TTORNEY to the c-wire of which an alternating current of 450 cycles per second is connected over the line nders LF2, LFI. A cold-cathode tube such as L is connected together with a test relay Tr to each of the five brushes, whereas that part of the circuit comprising relays RI, R2, R3, Sr, Srl, Vr and the potentiometer Pt is common to all the tubes L and the test relays T1'. As soon as the device for the identification of a call becomes operative, a starting relayvA1` is energized and a circuit is closed for the power magnet P of the switch F over a front contact of Ar and back contact of relay R2. At the same time battery is connected via the outer front contact of relay Ar to the winding of relay Rl causing this relay to operate, since the circuit is closed over the back contact of test relay Tr. If, during this hunting movement which is performed by the nder brushes, a c-wire is found to which an alternating potential of 450 cycles per second is connected, the cold-cathode tube L will iire and the test relay Tr will be energized, as already described. The attraction of the armature of relay Tr opens the circuit of relay RI which relay releases very quickly connecting the relay R2 to the sixth or test brush of the nder F: for the purpose of making a direct` current test.

If the line is free, the potential on the test brush will be sufficiently high to energize relay R2 which opens the circuit of the power magnet P and arrests the nder F. Over a iront contact lof relay R2, relay R3 is connected in series with a second low resistance winding of R2 whereby the potential on the test brush is reduced to such an extent that another iinder will not react when testing this potential; thus only one identi- 'cation finder will stop in the required position. Relay R3 closes a circuit over its front contact and the right hand back contact of relay RI for a sensitive and slow release relay Sr which operates and in turn closes a circuit for another slow release relay Srl which now performs the following functions: 1

1. It connects the direct current test relay R2 to the sixth or test brush of the line nder indel pendently of the contacts of relay RI.

2. It connects battery to the winding of relay R'I which thereby becomes independent of the starting relay A1'. 3. It closes a circuit for relay Vr including a common interrupter Int.

4. It closes a contact X by which further functions oi the identification circuit of which the nderF forms part, are initiated.

Relay Vr opens and closes the circuit of the test relay Tr at the periodicity of the interrupter 'Intl In consequence the main gap of the coldcathode tube L is periodically extinguished and this tube is, therefore, periodically restored to the condition in which it may respond repeatedly to the 'original signal so long as this signal appears to be present on the .c-wire.

In the arrangement illustrated in the drawing, the main gap ofthe cold-cathode tubeV is extinguished by interrupting the anode-cathode circuit. It will be evident, however, that other arrangements are possible by which the gap may be extinguished, for example, by reducing the potential between the electrodes A and e2 of the main gap below the'limiting potential at which discharge is still possible.

When the test relay Tr releases its armature, relay RI again energizes. Due to the slow release operation of relays Sr and Srl, relay Srl will, however, not release if lthe interruption takes 4 place for a period of time as determined by the interrupter Int. In case, however, the time of interruption Vis longer because, for example, the original signal is no longer present on the c-wire and the tube L and the test relay Tr are no longer energized, then the relay Srl will release causing the circuit to be restored entirely to its original condition. If'the rst response of the tube L is caused by a disturbing impulse kick it will not again react after the rst interruption of the circuit of test relay Tr which will, therefore, remain in a deenergized condition. Relay RI is operated and relay Sr is deenergized; thereafter, relay Srl releases and is followed by the release of relays Rl, R2 and R3. If the starting relay Ar is still operated, then relay RI will remain energized and the brushes of the finder F will again start their rotation. If the starting relay Ar is not energized the finder F will remain at rest. In the case of a premature release, relay Srl .will remain 4opera-ted:untilthe moment at which the alternating current of 450 cycles Der second Vis removed from the c-wire.

One embodiment only of the invention has been illustrated and described in 'detail' but it is to be understood that the invention is not limited lto the specic embodimentr described in detail.

For example, in well knownmanner the signal receiver may be so arranged that it does not perform its complete operation upon the first response or iiring of the cold-cathode tube L but only after this tube has been restored at least once to its starting condition by means of the interrupter Int. In 'this manner a sudden impulse kick will not cause the response of the signal receiving apparatus since when the second test is made the condition which initiated the operation will no longer be present.

What is claimed is:

l. In a signalling system, a signalling line, a gas discharge tube including a discharge gap, a current responsive device in circuit with said discharge gap, a control device,'means under the control of said current responsive device and convnecting said current responsive device to said control device for actuating said control device, means for applying a signal received over said line to -said gas discharge tube to strike said discharge gap and energize said current responsive device, and means under control of said control device for periodically extinguishing said gap and restoring the current thereof to normal during the period that said signal is applied to said line.

2. In a signalling system, a gas discharge tube comprising a plurality of electrodes including a pair of eleotrodes'for'ming a' discharge gap, a rst electric relay in the circuit of said discharge gap, a second slow-release electric relay in a circuit controlled by said iirst electric relay, means for applying a signalvoltage to an electrode of said 'tube to strike said discharge gap and actuate said rst relay, and means 'under the control of said second relay and operated-'during the operation thereof for periodical-ly extinguishing said r gap and restoring the circuit thereof to normal during the period that said signal 'voltage is applied to said tube'.V p Y 3. In a signalling system, a gas discharge tube lcomprising a main discharge gap and an auxiliary -the said main gap and energize said vrst relay,

and means under the control -'o'f said second relay and operated during the operation thereof for periodically extinguishing said main gap and restoring the circuit thereof to normal during the period that said signal voltage is applied to said auxiliary gap.

4. In a signalling, system, a gas discharge tube comprising a main discharge gap and an auxiliary discharge gap, a first electric relay in the circuit of said main gap, a second electric relay in a circuit controlled by said first relay, means for applying a signal voltage to said auxiliary gap to strike the said main gap and energize said first relay, and means under the control of said second relay and operated during the operation thereof for periodically interrupting and restoring the circuit of said main gap during the period that said signal voltage is applied to said auxiliary gap.

5. In an electric signalling system a gas discharge tube comprising a main discharge gap and an auxiliary discharge gap, a rst electric relay in the circuit of said main gap, a second slow-to-release relay in a circuit controlled by said iirst relay, means for applying a signal voltage to said auxiliary gap to strike said main gap and energize said rst relay, and means under the control of said second relay and operated during the operation thereof for periodically interrupting the circuit of said first relay.

v6. In an electric signalling system, a gas discharge tube comprising a plurality of electrodes including a pair of electrodes forming a discharge gap, means for applying a predetermined potential across said discharge gap, a first electric relay in the circuit of said discharge gap, a second electric relay controlled by said first relay, means for applying a signal Voltage to an electrode of said tube to strike said discharge gap and energize said first relay, and means under the control of said second relay and operated during the operation thereof for extinguishing said gap and after a predetermined interval for reapplying said predetermined potential across said gap.

7. In a telecommunication system a plurality of lines, a line identifying switch comprising contacts connected to said lines and a movable wiper, a gas discharge tube having a main gap and an auxiliary gap, means for applying a predetermined potential across said main gap, an electrical coupling between said wiper and said auxiliary gap, means for applying an identifying potential to a predetermined one of said lines, means for closing a driving circuit for said switch, an electric relay in the circuit of said main discharge gap which is energized when said wiper engages said last-mentioned line and said main gap strikes, a second relay under the control of said first relay for controlling the opening of said driving circuit, and means under the control of said second relay for extinguishing said main gap and after a predetermined interval for reapplying said predetermined potential across said main gap- 8. In a telecommunication system a plurality of lines, a line identifying switch comprising contacts connected to said lines and a movable Wiper, a gas discharge tube having a main gap and an auxiliary gap, means for applying a predetermined potential across said main gap, an electrical coupling between said wiper and said auxiliary gap, means for applying an identifying potential to a predetermined one of said lines, means for closing a driving circuit for said switch, an electric relay in the circuit of said main discharge gap which is energized when said wiper engages said last-mentioned line and said main gap strikes, a second relay under the control of said first relay for controlling the opening of said driving circuit, and means under the control of said second relay for periodically extinguishing said main gap and restoring the circuit thereof to normal during the period that said identifying potential is applied to said line.

9. In a telecommunication system a plurality of lines, a line identifying switch comprising contacts connected to said lines and a movable wiper, a gas discharge tube having a main gap and an auxiliary gap, means for applying a predetermined potential across said main gap, an electrical coupling between said wiper and said auxiliary gap, means for applying an identifying potential to a predetermined one of said lines, means for closing a driving circuit for said switch, an electric relay in the circuit of said main discharge gap which is energized when said wiper engages said last-mentioned line and said main gap strikes, a second relay under the control of said rst relay a test wiper for said switch, a connection from said test wiper to a winding of a test relay said connection extending over contacts of said second relay, a slow-release relay under the control of said second relay, and means under the control of said slow-release relay for periodically interrupting the circuit of said first relay.

CHARLES DE VRIENDT. LUCIEN A. B. CABES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,977,256 Swart Oct. 16, 1934 2,177,843 Seely Oct. 3l, 1939 2,252,766 Holden Aug. 19, 1941 2,270,246 Bascom Jan. 20, 1942 2,284,870 Holden June 2, 1942 2,319,424 Maloney May 18, 1943 FOREIGN PATENTS Number Country Date 55,722 Netherlands Dec. 15, 1943 

